Cryostratigraphy of late Pleistocene syngenetic permafrost (yedoma) in northern Alaska, Itkillik River exposure
Cryostratigraphy of late Pleistocene syngenetic permafrost (yedoma) in northern Alaska, Itkillik River exposure
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DOI：
10.1016/j.yqres.2010.12.003
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发表时间：
2011-05-01
影响因子：
2.3
通讯作者：
Stephani, E.
中科院分区：
文献类型：
--
作者：
Kanevskiy, M.;Shur, Y.;Stephani, E.
在更新世的寒冷气候下，欧亚大陆和北美的无冰川地区广泛发育着极其富含冰的同生永冻层。在阿拉斯加州，叶多马出现在苏厄德半岛的北方北极山麓。在阿拉斯加内陆。沿阿拉斯加北方Itkillik河下游沿着高33米的暴露为研究未经修改的yedoma提供了机会，包括地层学，粒度分布，土壤碳含量，形态和分离，楔形和热喀斯特洞穴冰的数量。出露的冻土序列由7个冰冻地层单元组成，形成于> 48000 ~ 5000 C-14 yr BP的时期，包括：1）活动层; 2）上部冻土的中间层; 3-4）两个不同厚度的同生冰楔的Yedoma粉砂单元; 5）埋藏泥炭层;（7）短冰楔型粉砂层。这种暴露与俄罗斯著名的Mus-Khaya和Duvanny亚尔耶多马暴露相当。根据我们的实地观察，文献资料，卫星图像和航空摄影的解释，我们已经制定了一个初步的地图yedoma在阿拉斯加州的分布。(C)2010年华盛顿大学。爱思唯尔公司出版All rights reserved.
Extremely ice-rich syngenetic permafrost, or yedoma, developed extensively under the cold climate of the Pleistocene in unglaciated regions of Eurasia and North America. In Alaska, yedoma occurs in the Arctic Foothills, the northern part of the Seward Peninsula. and in interior Alaska. A remarkable 33-m-high exposure along the lower Itkillik River in northern Alaska opened an opportunity to study the unmodified yedoma, including stratigraphy, particle-size distribution, soil carbon contents, morphology and quantity of segregated, wedge, and thermokarst-cave ice. The exposed permafrost sequence comprised seven cryostratigraphic units, which formed over a period from >48,000 to 5,000 C-14 yr BP, including: 1) active layer; 2) intermediate layer of the upper permafrost; 3-4) two yedoma silt units with different thicknesses of syngenetic ice wedges; 5) buried peat layer; 6) buried intermediate layer beneath the peat; and 7) silt layer with short ice wedges. This exposure is comparable to the well known Mus-Khaya and Duvanny Yar yedoma exposures in Russia. Based on our field observations, literature sources, and interpretation of satellite images and aerial photography, we have developed a preliminary map of yedoma distribution in Alaska. (C) 2010 University of Washington. Published by Elsevier Inc. All rights reserved.